AE92 Fuel Rail / 3SGE Injectors. Fuel Rail leaking @ No 4 Injector

[GeeEss]

Running Quads on a Bigport; trying to do pre-tune WARI set up but can't get to first base due to fueling issues. . .

Fuel is leaking (or more accurately; dribbling/pouring) past the O-ring seal on# 4 injector.

I have changed all the rubbers on the injectors; pads/ O-rings & spacers but fuel is still pissing past the seal on #4 and I'm at a loss as to why.

O-rings:

1. The 3SGE injectors came with O-rings; they looked serviceable so I used them.
2. I had 4 new AE92 injector O-rings so put these on the 3SGE injectors to see if they'd make a difference; they didn't
3. I then went out & got 4 new 3SGE O-rings < different part numbers to AE92 units but look identical to naked eye. That didn't fix the problem either.
Can anyone confirm if AE92/3SGE injector O-rings have identical cross-section (or otherwise).


Fuel Rail:

I have never had a problem with the rail before (with OEM injection) and haven't touched the Fuel rail so can't see why it would be that.


Spacers:

The 3SGE injectors have a higher shoulder than those on the AE92 so when you put AE92 spacer pads on them they concertina flat < photo shows old loose & sloppy spacers - changed them 4 new ones but it didn't stop the leak*>. Also tried mounting injectors w/out the spacers - no difference, still leaking at #4. . .

* As they are just pads not seals this was no surprise.


Blockage?

When I first activated the Pump; fuel was pissing past the Union on the Fuel Filter, so I tightened the bolt; then the leak moved to the 22mm bolt/pulsation Dampener union, so I tightened that up. Now its at the Injector itself so maybe there's a pressure build up somewhere?

Help. . . .

[jonathan yee]

all i can assume ids the o ring isn't sealing due to damage on the fuel rail? did you check for any scoring?

[banana_socks]

Swap the injectors around, will determine whether its the injector or the #4 fuel rail port. I'd hazard a guess its a problem with the rail. Couldn't be too hard to track down another for testing.

[GeeEss]

Sorry; should have said - I did swap the injectors around & confirmed it was the #4 Port.

I did also check the injector ports and all seemed to have; not so much scoring but definitely scuffing. . . . . Still not sure what I should do; its not like I have factory dimension specs to hand for the ports.

Have checked ToyoDIY and part was only used on JDM cars so no getting a used unit locally < probably not an option either - any parts 20+ years old. . .>

Or maybe it's none of the above. . . How often do Fuel Pressure Regulators go on these things, and how do I test one (with Engine OFF)?

[allencr]

Or maybe it's none of the above. . . How often do Fuel Pressure Regulators go on these things, and how do I test one (with Engine OFF)?

IT IS NOT too much pressure. The O-ring is twisted/cracked or seating on bad surface/s or the injector is at an angle.

[thechuckster]

What he said ^^ if the injector is inserted dry or on an angle you can distort the o-ring it can fail to seal or tear.

[GeeEss]

I don't think it's the O-ring. . .

OEM 3SGE & AE92 O-rings are roughly 8mm I.D. x 2mm Dia x-section. I replaced these with 6mm I.D. x 2.5mm x-section and that stopped the leak at the injector - but moved it to the FPR!!!

Is it possible I have a dud Fuel Pressure Regulator?

PS: A little "history" regarding this leak;

1. When I first fired up the fuel pump; fuel was pissing past the Filter union; so I tightened that.
2. After this fuel leaking past the Pulsation Dampener union; so I tightened that. . .
3. After that the leak moved to the O-ring on # 4 Injector, so I changed to a non OEM O-ring and that leak stopped, but moved to . .
4. Where it is now - the FPR O-ring. . . .

[thechuckster]

(goes back to first post) What 3SGE did those injectors come out of? Colour & body shape don't look denso? Or are they non-OEM replacements?

Also, changing to a smaller ID o-ring might lead to an early failure of the seal. By stretching it more (e.g. using 6mm ID instead of 8mm ID) around the injector body you loose some of the flexibility of the o-ring material that lets it do it's job. When mounted in the head & rail (and fitted to the rail with petrol as a lube), you should be able to easily rotate them and the seal still function. It looks like you've tightened them up super hard (judging by the squish of the spacer pads) as well as stretching them so movement/rotation of the injectors is likely to lead to the o-ring tearing or scoring resulting in a leak.

Also, are they at the right angle? if they're too long, they may not be sitting squarely in the bores of the rail which will allow the o-ring to leak.


To check the FPR, remove from rail, find a largish syringe and attach length of vacuum hose from it to vacuum port on FPR, apply as much vacuum (with the syringe) as you can, attempt to blow thru rail connection of FPR, you should be able to with only a few psi of pressure (without the vacuum you need to apply 35-38psi to flow any air past the regulator.

Otherwise disconnect return line to tank from FPR and feed into a bucket, turn on fuel pump, should flow some fuel with pump on, if you apply a vacuum to the FPR (as per above) will flow more.


If you fit the original AE92 injectors to the rail, does it still leak?


Finally, have the leaking o-rings been cleaned with WD40 or a similar product? some o-ring and seal material material (note: not sure about fuel-safe items like injector o-rings) will go permanently soft and expand if soaked in that stuff (brake piston seals for instance are rooted if washed with WD40).

[JP]

sounds like a dodgey FPR to me, those are the OEM toyota injectors made by Aisin from a late 3sge, same body style as the injectors used in the vvti 1J's, 1zz, 2zz etc.